[FFmpeg-devel] [GSoC] Patch which add simple P frame support for ffv1

[Michael Niedermayer]

On Fri, Apr 24, 2015 at 12:03:38AM +0800, Yingming Fan wrote:
> Hi, everyone.
> 
> This is my GSoC qualification task, add simple P frame for ffv1.
> 
> P frame will work when you add -level 4.
> 
> eg. ffmpeg -pix_fmt yuv420p -s xxxx -i xx.yuv -vcodec ffv1 -level 4 test.nut
> 
> Notice: Only support yuv colorspace and 8 bit currently, i will support
> these in later time.
> 
> Other option about ffv1 can be find here:
> http://trac.ffmpeg.org/wiki/Encode/FFV1
> 
> About test.
> 
> I haven't send FATE result to server as i'm not that familiar with those
> staff. But i will complete this as soon as possible.
> 
> Best regards

>  ffv1.c    |   10 +++++++
>  ffv1.h    |    1 
>  ffv1dec.c |   54 +++++++++++++++++++++++++++++---------
>  ffv1enc.c |   87 ++++++++++++++++++++++++++++++++++++++++++++++++++------------
>  4 files changed, 124 insertions(+), 28 deletions(-)
> 56a6b95f90706b65b833f1a359c08f927fdc1124  0001-Add-simple-P-frame-support-for-ffv1.patch
> From 5fcc87093ce1f2aea3a43b52399b09fdf8acda36 Mon Sep 17 00:00:00 2001
> From: Yingming Fan <yingmingfan at gmail.com>
> Date: Thu, 23 Apr 2015 23:19:05 +0800
> Subject: [PATCH] Add simple P frame support for ffv1.

breaks ffv1 with normal intra frames:
./ffmpeg -i matrixbench_mpeg2.mpg -vf format=gbrp10 -vcodec ffv1 -t 1 test.avi
just segfaults

./ffmpeg   -i matrixbench_mpeg2.mpg  -vcodec ffv1 -level 3 -t 1 test-3.nut
./ffmpeg   -i matrixbench_mpeg2.mpg  -vcodec ffv1 -level 4 -t 1 test-4.nut

-rw-r----- 1 michael michael 2325508 Apr 23 18:24 test-3.nut
-rw-r----- 1 michael michael 3394282 Apr 23 18:24 test-4.nut

the file with P frames is 50% bigger, thats not a good start,
considering the goal is to improve compression of the currently
existing FFV1

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Asymptotically faster algorithms should always be preferred if you have
asymptotical amounts of data
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